Automatic stoker



' L46300 l.. R. s'rowE' AUTOMATIC STOKER Filed June 1e j 1919 5sheets-sheet 2 July 31, 1923. l

l.. R. sTowE AUTOMATIC sToKER' i File@ June' 16.' 191s;- s sheets-,sheet5 July 31, E923.

. L. R.v STOWE AUTOMATIC sToKER Filed Junejle. 1919 #2236551? ZE./jfozzz y5 Sheets-,Sheet 5 sof f being Application led June 18, 1919.Serial No. 304,584.

'To all whom z't may com em.'

' Be it `known that I, Lern R. Srown a citizen of the United Statesresiding at Maplewood, in the county of t. Louis and State of Missouri,have invented certain new and useful Im rovements in Automatic Stokers,of. which die following is a specification.

This invention relates to improvements in stokers, and its purpose is toprovide an improved automatic stoking devicein which the under-feedprinciple is combined lwith means for securing a positive feed Aof thefuel throughout the length of the grate.

It is we known that in the ordinary under-feed Stoker, it is impossibleto secure a uniform and sitive movement of fuel toward 4the disc argeend of the grate or to secure and maintain a uniform condition of thefuel bed especially when thin lires are carried. t is well known thatinthe usua type of underfeed Stoker a large quantity of fuel containinghlgh percenta of combustibles reach the discharge en of thestoker,where, for the sake of economy, it must be held untilzfthe combustion isnearly completed, while .other parts of the fuel reach the dischar e endo the grate uite well.consumed,an for the purpose o avoiding clinkersthese' other vparts must be immediately discharged to the ash it. Thediculty caused by this irreguljarity is increased by the absence in theusual under-feed stoker of a positive and continuousfmeans ofdischarging the refuse. These .defects in the under-feed stoker havebeen overcome in the present invention by combining a plurality ofunder-feed devices with a p ura ity vof grate chains which are arrangedin alternation, so that the fuel which is moved upwardly by theunder-feed devices is positively moved along the grate by the movlngchains, thereby securing a positive feed of the fuel from one end of thegrate to the other and a positive discharge of the ash at the lower endof the grate. B means of the present invention, it is possigle to adjustthe movements of the underfeed devices and the moving chains in order tosecure any desired depth and condition gf the fuel over any part ofthegrate surace. Y

The nature of the invention and the various objects to be attainedthereby will be understood from the following specification,

taken'in connection with theaccompanying.

drawings, in which one embodiment is illustrated.

In the drawings- Figure 1 shows a top plan view of my proved stoker,parts of the same being removed for the sake of clearness;

Fig. 2 shows an end elevation of the for'- ward end of the Stoker, partsof the 'same being removed.

Fig. 3 shows a side elevation of the Stoker;

Fig. 4 shows a loi'gitudinal sectionalview on the line 4-4 of .Fig 5shows a partial transverse sectional View on the line 5-5 of Fig. 3; and

Fig. 6 show s a partial transverse sectional view on the line 6-6 ofFig. 3.

The mechanism of the stoker is su on a foundation 10 of concrete or t elike which is preferably arranged in a series of steps Y10, 10", and 10,A conduit 11 is provided between the foundation, pressure is suppliedthrough this conduit to the underside of the grate, the flow of airbeing regulated by a valve 12. The Stoker comprises a .pair of sideframes 14 which-are provided with upper and lower parts 14n, letb and14, respectively, ada ted to rest upon the steps 10, 10b and 10c o thefoundation. One or more intermediate center frames 15' are locatedbetween the side frames 14 and each center frame is provided with parts155, 15b and 15c the parts A10, 10", and 10, respectively, of thefoundation.

The side frames and the center frame carry the fuel feeding mechanismwhich comprises a plurality of under-feed retorts 16 which extenddownwardly substantially throughout two-thirds of the'length of thegrate and which are arranged in alternation with a plurality of endlessflexible grate chains 17 Aextendin throughout the lenh of the grate. Ap1 urality of other exile chains 18 are mounted between the .chains 17from the lower ends-of the under-feed retorts 16 to the discharge end ofthe ate, and the lower portions of the chains 1 and the chains 18 have alesser inclination to the horizontal than the fuel retorts and the upperparts of the chain 17, as shown particularly in Fig. 4. The lower endsof the side frames and the center frame have' their upper partsconstrutedto conform to the conthe two upper steps of and o, blast ofair under which rest uponl ported i Too Vcranks 30a in oppositedirections, so that one of thev formation of the upper surface of thegrate. The inclination of the upper portion 'of the grate surfacepreferably approximates the angle of repose, but it is found in practicethat an angle of about 20o is a suitable angle of inclination for mostfuels, and the decreased inclination of the lower part of the gratesurface is provided in order to effect a retardation of the fueladjacent the lower end of the grate.

The fuel retorts 16 comprise metal troughs 20 whi^h are rectangular incrosssection` as shown in Fig. 5, and tapered toward their lower ends,so that the depth of each trough gradually decreases toward the lowerend of the grate.- rlthese troughs are supported at their upper ends ona transverse -beam 21 which has its ends secured to the side frames 14by means of angle plates 22. The -beam 21 is supported between its endsby one or more posts 23 which rest directly on the foundation 10a. Thelower portions of the troughs 2() are supported by transverse -beams 24which are secured to the upper side of the center frame 15 and to theinner walls of the side frames 14. the lower parts of the troughs beingprovided with downwardly extending portions 20a which are secured to thelower I-beam 25. The upper end of each trough is provided with a topwall 20b which Acooperates with the side walls and the lower wall of thetrough to form a' guideway for a fuel pusher or ram 27. These pushersreciprocate in their guides to push the fuel downwardly onto the gratesurface and they are operated by connecting rods 28 which are detachablyconnected through bearing blocks 29 with the cranks 30a of a crank shaft30 journalled in bearings 31 carried by the troughs 2() and in bearings32 carried by the side frames 14. The alternate of the crank shaft aredirected pushers 27 is in its uppermost position when the next adjacentpistons are in their lower positions.

The crank shaft 30 extends through one of the side frames 14, and hasits outer end journalled in a bearing 33 carried by an auxiliary frame34 which is secured to the side frame. A gear 35 is secured to the shaft30 between the'side frame and the bearing 33, and this gear is adaptedto mesh with a pinion 36 secured to an intermediate shaft 37. The shaft37 also has fixed thereon a gear 38 which meshes with a driving pinion39 secured to the shaft 40 journalled in bearings cr-rre'l by the upperparts of the side frame and the auxiliary frame 34. The shaft 40is'driven by a ratchet wheel 41 which is fixed fhereon and adapted to beengaged by a '.awl 42 pivoted on the bell crank 43 which has its otherarm 43a connected to an operatinfr rod 44. The rod 44 may bereciprocated in their guides.

raeaaoo by any desired mechanism in order to effect the rotation of theratchet wheel and the consequent rotation of the crank shaft 36 whichcauses the pushers 27 to reciprocate The fuel to be burned is fed to thegrate from a hopper 45 which comprises an inclined lower wall 46 and avertically movable feed gate 47 by which the size of the outlet opening48 may be controlled. 'llhe furnace arch 49 of fire brick or the likeextends upwardly and rearwardly from the feed gate 47, and the spacebetween the lower wall 46 of the hopper and the foundation 10 is closedacross the front end of the furnace by a front wall 5() of sheet metal,or the like, which may be provided with a plurality of openings topermit access therethrough to the operating mechanism of the Stoker.rlhe fuel which .passes through the outlet opening 48 drops into theretorts formel by thetroughs 20, and the pushers 27 engage the fuel andpush it downwardly in the inclined troughs, so that it is graduallyforced upwardly onto the fuel bed beneath theburning fuel. edges of thesidewalls of the troughs it passes thereover onto the chains 17, each ofwhich is formed of a plurality of series 17a of alining links 51. Thelinks in one series overlap those in the adjacent series, and connectingpins 52gextend transversely therethrough to form a pivotal connectionbetween the links of the chain. Portions of the innermost links ofeach'chain are cut away on their inner sides, as shown at 53, to receivesprocket wheels adapted to engage the pivot pins or connected parts foradvancing the endless grate chains and all of the links are providedwith grooves in their sides to form apertures for permitting the flow ofair to the fuel. The form of grate chain herein shown together withmeans to vary the tension thereof is more fully illustrated anddescribed in my United States Patent No. 1,379,135 granted May 24, 1921.

At the upper end of the grate, the chains 17 are mounted on idler wheels55 which are located between the fuel retort-s and adapted to rotate onthe crank shaft 30 between fixed collars 56. At the lower end of thegrate, the chains 17 extend around sprocket gears 58 which are securedto a drive shaft 60 extending transversely of the furnace and mounted inbearings 61 carried by the side frame and a bearing 62 carried by thelower portion of the center frame 15. The bearing 62 is open on itsupper side and is provided with a slot 63 to permit the insertion of theshaft. rlhe chains 17 also pass over chain supportingl wheels 64 mountedon a shaft 65 which is supported by bearings 66 carried by the sideframe and by a bearing 67 carriedby the center frame, the bearing 67being open on its upper side to permit the As the fuel rises above theupper j rca insertion of the shaft. The shaft carries a plurality ofother chain supporting wheels 69 which are located beneath the lowerends of the troughs 20 and the lower driving shaft 60 carriesa-plurality of fixed sprocket ars 70 which are in alinement with the weelsv 69. The short flexible chains 18 which extend from the fuelretorts to the lower end of the grate are mounted on the wheels 69 andsprocket gears 70 and are formed of complementary links which areconnected together in the manner that the links of the chain 17 thelower end of the middle fuel retort which is located above the centerframe l5 is preferably occupied by two chains 18 which are spaced apart,and the lower part 15d of the center frame extends upwardly betweenthese chains with the upper surface thereof in alinement with thegratesurface formed by the upper surfaces ofthe links. The upper and lowerstretches of the chains 17 and 18 are supported by tubular rollers 72which are'adapted to rotate on rods 73 extending between the side framesand the center frame 15.4 These rods are detachably carried by the framemembers and may be secured in position by nuts 74 or by other suitablemeans which will permit the ready removal of said rods. The upperstretches of the chain 17 are supported between the fuel retorts by danes 75 which are formed integrally with t e lateral walls of the troughsand extend transversely thereto.

Both the chains 17 and the chains 18 are driven by the lower shaft 60,which has a worm-wheel 76 secured to the end thereof, and this worinwheel 77 which is secured to the lower end of a shaft 78 journalled inbearings 79 secured to the side frame 14. The shaft 78 extends upwardlyto the forward end of the Stoker where it is journalled in a bracket 80secured to the forward end of the side frame. A ratchet wheel 81 issecured to the shaft 78 between'the )arms of the bracket 80, and thisratchet wheel is adapted to be driven by a pawl 82 which is pivoted onone arm of a bell crank lever 83, the other arm of this lever beingpivotally connected to an operating rod 84 which may be reciprocated byany desired mechanism in order' to operate the drive shaft 60 and therebactuate the chains. In the operation of t e Stoker, the feed gate 47 mabe located in any desired position in or er to adjust the relativeaction of the under-feed mechanism and the dexible chains in advancingthe fuel over the grate. When raised substantially above the gratesurface, the gate 47 permits the coal to fall onto the chains as well asinto the troughs, so that some fuel is carried downwardly onto the grateby the .advancing chains, and an additional quantity of fuel is fed ontothe grate by the downward moveany n.,

are connected. The space belowis engaged by a wormy ments of the pushers27. The positive feed of the chains is thus combined with the 4operationof the under-feed mechanism, so that a greater uniformity in thethickness of the entire fuel bed is maintained, 'while at the same timean adequate air supply is provided through the air spaces of the chains.The front wall 50 confines the air blast at the forward end of thestoker and a sheet metal partition is also preferably provided acrossthe ends of the side frames beneath the lower end of the grate in orderto separate the air chamber from the ash pit. The chains carry the fuelpositively from the upper part of the grate to the ash pit, and thelesser inclination of the lower part of the grate operates to'retard thefuel and to effect a thickening of the fuel bed adjacent the bridgewall, so that the burning out of the fuel bed v without interfering witha positive discharge of the ash. lf the feed gate 47 be lowered until itrests directly on the upper parts of the fuel troughs, chains inconveying fuel directly from the fuel hopper is eliminated, and the fuelis fed to the I" te b the under-feed mechanism alone aer whlchthe chainscooperate with the pistons to advance the fuel downwardly throughout thegrate surface. The action of the stoker can be regulated by adjustingthe speed of the ratchet mechanism by which the chains are operated andby adjusting the ratchet mechanism by which the underfeed mechanism `isoperated. If the chains run relatively slow there will be a greateraccumulation of ash on the lower stretches of the chains, and thethickness of the fuel bed at the lower end of the grate will beincreased. 'lhe use of one or more center frames 15 makes it possible toincrease the width of the Stoker to any desired extent while at the sametime providing the necessary support for the intermediate parts of thegrate.

Although I have shown and described one embodiment of the invention forpurposes of illustration, it will be understood that it may beconstructed in various other forms without departing from the scope ofthe 'appended claims.

What I claim is:

1. rThe combination in a Stoker of spaced grate chains inclineddownwardly at their forward portions, feeding troughs, pusher memberscoacting therewith, said trou hs being mounted between said spacedchains and having the sides thereof tapered to accord with theinclination of said chains, and substantially horizontal endless chainslocated at the extremity of each of said troughs between said firstnamed chains adapted to retard the movement of the fuel at the forwardend of the Stoker.

2. The combination in a Stoker of a pair trough, means of side frames, afuel trough mounted hetween said side frames, endless rate chainsmounted on opposite sides o said fuel trough, a crank shaft journalledin said side frames, a pusher mounted in said fuel for operativelyconnectin said pusher with said crank shaft, a secon shaft mountedparallel to said crank shaft, a series of sprocket gears fixed on saidsecond shaft, a lurality of chain supporting Wheels rotata ly mounted onsaid crank shaft, said grate chains being mounted on said sprocketgears, and said chain supporting wheels, and means for of said shafts.

3. rlhe combination in a stoker of a pair of'side frames, a fuel troughmounted hetween said side frames and extending through a portion of thelength of the grate, an endless grate chain extending in alinement withsaid fuel trough through the reactuating each receso@ maining portion ofthe length of the grate, a shaft journalled in saidside frames adjacentthe feeding end of the grate, means actuated by said shaft for advancingfuel in said trough, a second shaft journalled in said side framesadjacent the lower end of said trough, a third shaft journalled in saidframes adjacent the lower end thereof, wheels mounted on said secondshaft and sprocket gears on said third shaft for supporting said endlessgrate chain, other wheels mounted on said first-named shaft and othersprocket gears on said third shaft, other grate chains extendingthroughout the length of the grate on opposite sides of said fuel troughand supported by said other wheels and sprocket gears, and means fordriving said third shaft.

ln testimony whereof, l have subscribed my name'.

LQYD R. STOWE.

